Method for the control of weeds



States This application is a continuation-in-part of patent applicationSer. No. 208,904 filed July 10, 1962, now abandoned. This inventionrelates to the control of pests with novel pesticidal compositions. Morespecifically, this invention relates to the method for the control ofweeds which comprises contacting said weeds with a herbicidalcomposition comprising an inert carrier and as the essential activeingredient, in a quantity which is toxic to said weeds a compound of thegeneral formula wherein n is a whole number from 1 to 3; R and R areselected from the group consisting of lower unsubstituted alkyl, lowerunsubstituted alkenyl, lower monohydroxyalkyl, and hydrogen, a maximumof one of R and R being hydrogen; and R" is a phenyl radical containingsubstituents selected from the group consisting of lower unsubstitutedalkyl, lower unsubstituted alkoxy, lower unsubstituted alkylmercapto,halogen, mercapto, nitro, hydroxy, and amino, provided that onesubstituent on the phenyl radical is halogen when one lowerunsubstituted alkoxy substituent is present on the phenyl ring, andprovided that a maximum of three substituents on the phenyl ring arehydrogen when one substituent on the phenyl ring is nitro. By loweralkyl, lower alkenyl, and lower alkylmercapto are meant those groupscontaining up to four carbon atoms.

The chemical compounds useful in the pesticidal compositions accordingto this invention can also be represented by the following generalformula wherein n, R and R are as defined above and X X X X and X areselected from the group consisting of lower unsubstituted alkyl, lowerunsubstituted alkoxy, lower unsubstituted alkylmercapto, halogen,mercapto, nitro, hydroxy, and amino, provided that one of X X X X and Xis halogen when one of X X X X and X is lower unsubstituted alkoxy andprovided that a maximum of three of X X X X and X are hydrogen when oneof X X X X and X is nitro.

In a preferred embodiment of this invention, the compounds useful in thepesticidal compositions of this invention will have on the phenyl ring amaximum of two lower unsubstituted lower 'alkoxy groups, a maximum oftwo lower unsubstituted alkyl groups, a maximum of two nitro groups, amaximum of two amino groups, a maximum of two hydroxy groups, a maximumof two lower unsubstituted alkylmercapto groups, and a maximum of twomercapto groups.

Typical examples of chemical compounds which are useful in thecompositions for the pest control method of this invention are suchsubstances as N,N-diethyl-3-bromo-4-methoxybenzylamine,N-ethyl-3-bromo-4-methoxybenzylamine,N,N-diethyl-3-fluoro-4-methoxybenzylamine,

3,46,024 Patented Oct. 15, 1968 Many of such compounds useful in thecompositions according to this invention are known in the art. These andother similar compounds can be obtained, for example, by thecondensation of compounds of the formula wherein Y is chlorine orbromine and N, X X X X and X are as defined above, with amines HNRR',wherein R and R are also as defined above. The starting materials of thestructural formula given comprise the appropriately substituted benzyl,phenethyl, and propylbenzene chlorides or bromides. Typical examples ofsuch compounds useful in the preparation of active compounds for thisinvention include 2-chloro-6-nitrobenzyl bromide, 3,5- dinitrobenzylbromide, p-butylbenzyl chloride, 2,4-dinitrobenzyl chloride,p-ethylbenzyl chloride, 3,5-dimethoxybenzyl chloride, 2,6-dichlorobenzylbromide, 2-chloro-5- nitrobenzyl chloride, 2-nitro-5-chlorobenzylchloride, 2,5- dimethoxybenzyl bromide, 2,6-dimethoxybenzyl chloride,p-butylbenzyl chloride, 3,4-diethoxybenzyl chloride, pbromobenzylchloride, 2-ethyl-S-nitrobenzylchloride, opropylbenzyl chloride,2-ethyl-4-nitrobenzyl chloride, 4- ethyl-Z-nitrobenzyl chloride,2-methoxy-5-chlorobenzyl chloride, 3-bromo-4-methoxybenzyl chloride,2-methyl-4- methoxy-S-nitrobenzyl chloride,Z-methoxy-S-nitrobenzylchloride, o-aminobenzyl chloride,4-(methylthio)-benzyl chloride, 4-chlorophenethyl chloride,Z-chloro-S-methoxyphenethyl bromide, 3-chloro-4-methoxyphenethylbromide, 2-fluoro-4-methoxyphenethyl bromide, 4-tent-butylphenethylbromide, 3-ethylphenethyl bromide, 1-(3-bromopropyl)-4-tert-butylbenzene, o-hydroxybenzyl chloride,3,5-dibromobenzyl bromide, 2,4,6-tribromobenzyl bromide, and the like.

Suitable reactants of the formula HNRR include a Wide variety of primaryand secondary amines wherein R and R are as defined above. Some typicalsuitable reactants are, for example, isopropylamine, di-n-propylamine,dimethylamine, ethanolamine, methylamine, diethylamine,di-tert-butylamine, allylamine, diallylamine, 4-amino-1-butanol,3-amino-1-butanol, diethanolamine, methylethylamine, and the like.

When the condensation reaction to form compounds for this invention iscarried out, at least two moles of the amine should be used for eachmole of the chloride or bromide, since the hydrogen halide releasedduring the reaction is taken up by some of the free amine. The reactioncan be carried out conveniently by heating the reactants, preferably inan inert solvent such as benzene or toluene. The exact reactiontemperatures are not critical,

since the reaction will often take place at normal room temperature;however, temperatures which are the normal reflux temperature of thereaction mixture are preferred. The reaction will often be complete in afew hours. Generally, a precipitate of amine hydrochloride orhydrobromide will form in the reaction mixture and can be filtered off.The product can be isolated from the reaction mixture by etherextraction; and it can be purified by crystallization, fractionaldistillation, or other techniques known to the art.

Some typical compounds which are useful in the compositions and methodof this invention and which can be prepared in the manner describedabove are as follows:

N-ethyl-2,4-dinitrobenzylamine N-methyl-3 ,5 -dimethoxybenzylamineN,N-diethyl-Z,6-dichlorobenzylamineN,N-diethyl-2-chlor0-5-nitrobenzylamineN,N-dimethyl-2-ethyl-5-nitrobenzylamineN-isopropyl-Z-methoxy--chlorobenzylamineN,N-diisopropyl-4-(methylmercapto)benzylamineN-propyl-2-chloro-5-methoxyphenethylamineN,N-dipropyl-3-chloro-4-methoxyphenethylamineN-butyl-4-tert-butylphenethylamine N-allyl-o-hydroxybenzylamineN,N-diallyl-2,4,6-tribromobenzylamine N- 4-hyd1'oxybutyl)-p-butylbenzylamine N- (Z-butenyl) -3 -ethoxy-4-fluorobenzylamineN,N-di(2-hydroxyethyl) -2-ethyl-5-nitrobenzylamineN-isobutyl-4-chlorophenethylamine N-ethyl-Z-methoxy-5-bromobenzylamineN-methyl-2-chloro-6-nitrobenzylamineN,N-dimethyl-2-methyl-4-methoxy5-chlorobenzylamineN-ethyl-3,S-dibromobenzylamine.

The herbicidal compositions of this invention comprise an inert carrierand a herbicidally toxic amount of a compound R(CH ),,NRR as previouslydefined. Such compositions, which are usually known in the art asformulations, enable the active compound to be applied conveniently tothe site of the pest infestation in any desired quantity. Thesecompositions can be solids such as dusts, granules, or wettable powders;or they can be liquids such as solutions or emulsifiable concentrates.

For example, dusts can be prepared by grinding and blending the activecompound with a solid inert carrier such as the tales, clays, silicas,pyrophyllite, and the like. Granular formulations can be prepared byimpregnating the compound, usually dissolved in a suitable solvent, onto and into granulated carriers such as the attapulgites or thevermiculites, usually of a particle size range of from about 0.3 to 1.5mm. Wettable powders, which can be dispersed in water to any desiredconcentration of the active compound, can be prepared by incorporatingwetting agents into concentrated dust compositions.

In some cases the active compounds are sufiiciently soluble in commonorganic solvents such as kerosene or xylene so that they can be useddirectly as solutions in these solvents. However, preferred liquidcompositions are emulsifiable concentrates, which comprise an activecompound according to this invention and as the inert carrier, a solventand an emulsifier. Such emulsifiable concentrates can be diluted withwater to any desired concentration of active compound for application assprays to the site of the pest infestation. The emulsifiers mostcommonly used in these concentrates are nonionic or mixtures of nonionicwith anionic surface-active agents.

Typical compositions according to this invention are illustrated by thefollowing examples, in which the quantities are in parts by Weight.

EXAMPLE 1 Preparation of a dust N-butyl-2,4-dichlorobenzylamine Powderedtalc 90 The above ingredients are mixed in a mechanical grinder-blenderand are ground until a homogeneous, free-flowing dust of the desiredparticle size is obtained. This dust is suitable for direct applicationto the site of the pest infestation.

EXAMPLE 2 Preparation of an emulsifiable concentrate The followingingredients are blended thoroughly until a homogeneous liquidconcentrate is obtained. This concentrate is mixed with water to give anaqueous dispersion containing the desired concentration of activecompound for use as a spray.

N,N-diethyl-m-methylbenzylamine 25 Sodium lauryl sulfate 2 Sodium ligninsulfonate 3 Kerosene 70 EXAMPLE 3 Preparation of a Wettable powder Thefollowing components are mixed intimately in conventional mixing orblending equipment and are then ground to a powder having an averageparticle size of less than about 50 microns. The finished powder isdispersed in water to give the desired concentration of active compound.

N-ethyl-3-bromo4-methoxybenzylamine 75.00 Fullers earth 22.75 Sodiumlauryl sulfate 2.00 Methyl cellulose .25

EXAMPLE 4 Preparation of an oil-dispersible powder The followingcomponents are blended and ground as described in the previous exampleto give a powder which can be dispersed in oil to form a spraycontaining the desired concentration of active compound.

N,N-diethyl-Z-methoxy-5-brornobenzylamine 70 Condensation product ofdiamylphenol with ethylene oxide 4 Fullers earth 26 EXAMPLE 5Preparation of a granular formulation The following ingredients aremixed with sufficient water to form a paste, which is then extruded,dried, and ground to give granules, preferably from about to 4 inch indiameter. The granules are applied with fertilizer spreader equipment orother conventional apparatus. The dextrin in this formulation serves asa binding agent.

N,N-dimethyl-2-methoxy-3-chlorobenzylamine 10 Fullers earth 66 Dextrin20 Sodium lignin sulfonate 3 Kerosene 1 The compositions of thisinvention can be applied in any manner recognized by the art, Theconcentration of the active compounds in the compositions will varygreatly with the type of formulation and the purpose for which it isdesigned, but generally the compositions will comprise from about 0.05to about percent by weight of the active compounds. In a preferredembodiment of this invention, the compositions will comprise from about5 to about 75 percent by weight of the active compound. The compositionscan also comprise such additional substances as other pesticides,Spreaders, adhesives, stickers, fertilizers, activators, symergists, andthe like.

Weeds are undesirable plants in their growing where they are not wanted,having no economic value, and interfering with the production ofcultivated crops or with the welfare of livestock. Many types of weedsare known, including annuals such as lambsquarters, yellow foxtail,

French-weed, ryegrass, goose-grass, chickweed, and smartweed; biennialssuch as wild carrot, great burdock, mullein, round-leaved mallow, bluethistle, bull thistle, houndstongue, moth mullein, and purple starthistle; or perennials such as white cockle, perennial rye-grass,quackgrass, Johnson grass, Canada thistle, hedge bindweed, Bermudagrass, sheep sorrel, field chickweed, and winter-cress. Similarly, suchweeds can be classified as broad-leaf or grassy weeds. It iseconomically desirable to control the growth of such weeds withoutdamaging beneficial plants or livestock.

The compositions of this invention are particularly valuable for weedcontrol because they are toxic to many species and groups of weeds whilethey are relatively non toxic to many beneficial plants. The method ofthis invention for the control of weeds comprises contacting said weedswith a herbicidal composition comprising an inert carrier and as theessential active ingredient, in a quantity which is herbicidally toxicto said weeds, a compound R"(CH -NRR'.

The exact amount of compound required will depend on a variety offactors, including the hardiness of the particular weed species,weather, method of application, the kind of beneficial plants in thesame area, and the like. Thus, while the application of up to only aboutone or two ounces of an active compound per acre can be sufficient forgood control of a light infestation of weeds growing under adverseconditions, the application of one pound or more of active compound peracre can be required for good control of a dense infestation of hardyweeds growing under favorable conditions.

The present compositions are particularly effective in the control ofthe annual weeds, especially pigweed, crabgrass and wild mustard. Theseweeds can be effectively controlled by the application of a herbicidallyetfective amount. While this amount will vary with the weed species,equipment, specific identity of the chemical composition, terrain andother factors, applications of from about 2 to 10 pounds of activecompound per acre are useful.

The herbicidal toxicity of the compositions of this invention can beillustrated by many of the established testing techniques known to theart. For example, emulsifiable concentrate compositions can be dilutedwith water to concentrations equivalent to 4 pounds of the activecompound per acre. Duplicate paper pots filled with a sand and soilmixture are seeded with weeds; and immediately after seeding, the soilsurface of each pot is sprayed with an appropriately diluted testsolution. The weed growth is maintained under artificial lighting withirrigation provided by placing the porous pots in a small amount ofwater in stainless steel trays. The weeds are observed for a week to tendays; and the percent kill, injury, and stand reduction are recorded.The results indicate a high order of herbicidal activity of thecompositions of this invention. Comparable pre-planting orpost-emergence tests can also be used.

We claim:

1. The method for the control of weeds which comprises contacting saidweeds with a herbicidal composition comprising an inert carrier and asthe essential active ingredient, in a quantity which is toxic to saidweeds, a compound of the formula /R R(CIIZ)HN wherein n is a wholenumber from 1 to 3; R and R are selected from the group consisting oflower unsubstituted alkyl, lower unsubstituted alkenyl, lowermonohydroxyalkyl, and hydrogen, a maximum of one of R and R" beinghydrogen; and R" is a phenyl radical containing substituents selectedfrom the group consisting of lower unsubstituted alkyl, lowerunsubstituted alkoxy, lower unsubstituted alkylmercapto, halogen,mercapto, nitro, hydroxy, and amino, provided that one substituent onthe phenyl radical is halogen when one lower unsubstituted alkoxysubstituent is present on the phenyl ring, and provided that a maximumof three substituents on the phenyl radical are hydrogen when onesubstituent on the phenyl radical is nitro.

2. The method of claim 1, wherein R" is a phenyl radical substitutedwith one lower unsubstituted alkoxy group and one halogen atom.

3. The method of claim 1, wherein R is a phenyl radical substituted withtwo nitro groups.

4. The method of claim 1, wherein R" is a phenyl radical substitutedwith from one to two lower unsubstituted alkyl groups.

5. The method of claim 1, wherein R" is a phenyl radial substituted withone lower unsubstituted alkylmercapto group.

6. The method of claim 1, wherein R" is a phenyl radical substitutedwith from one to four halogen atoms.

7. The method of claim 1, wherein at least one of R and R is lowerunsubstituted alkyl.

8. The method of claim 1, wherein at least one of R and R is lowerunsubstituted alkenyl.

9. The method of claim 1, wherein the compound isN-butyl-2,4-dichlorobenzylamine.

10. The method of claim 1, wherein the compound isN,N-diethyl-m-methylbenzylamine.

11. The method of claim 1, wherein the compound isN-ethyl-3-bromo-4-methoxybenzylamine.

12. The method of claim 1, wherein the compound isN,N-diethyl-2-methoxy-S-nitrobenzylamine.

13. The method of claim 1, wherein the comp'ound isN,N-dimethylm-methoxybenzylamine.

References Cited UNITED STATES PATENTS JAMES O. THOMAS, JR., PrimaryExaminer.

U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, D.C. 20231 UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION atent No. 3,406,024October 15, 1968 Sidney B. Richter et al.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 6, line 12, "R" should read R Signed and sealed this 10th day ofMarch 1970.

SEAL) HCSI:

iward M. Fletcher, Jr.

ttesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR.

1. THE METHOD FOR THE CONTROL OF WEEDS WHICH COMPRISES CONTACTING SAIDWEEDS WITH A HERBICIDAL COMPOSITION COMPRISING AN INERT CARRIER AND ASTHE ESSENTIAL ACTIVE INGREDIENT, IN A QUANTITY WHICH IS TOXIC TO SAIDWEEDS, A COMPOUND OF THE FORMULA